1. Field of the Invention
The present invention relates to an elevator system for controlling a response to a call, and in particular to an elevator system for controlling a response to a call wherein a sub-controller, namely a hall controller determines service ability of an elevator car responding to a call, and a main controller, namely an elevator controller and a plurality of sub-controllers are periodically examined, which results in improved reliability and rapidity of the call response.
2. Description of the Background Art
FIG. 1 is a block diagram illustrating a conventional elevator system for controlling the response of an elevator car E moving between floors in a building to a call. The conventional elevator system for controlling the response to the call will now be described with reference to FIG. 1. A main controller MC is connected to a plurality of sub-controllers SC1-SCn disposed on each floor in a building via a serial communication line SL. An upper direction call button (hereinafter, `UP button`) UB, an upper direction response lamp UL, and a car position indicator CP1 are connected to the sub-controller SC1 provided on a lowest floor of a building through each signal line. A lower direction call button (hereinafter, `DOWN button`) DB, a lower direction response lamp DL, and a car position indicator CPn are connected to the sub-controller SCn provided on a highest floor of the building via each signal line. The UP button UB, the DOWN button DB, the upper direction response lamp UL, the lower direction response lamp DL and the car position indicator CP2-CPn-1 are connected to the sub-controllers SC2-SCn-1 positioned on the floors between the highest and lowest floors.
The main controller MC is a controller installed in a machinery room which is generally provided on the highest floor, and determines service ability of an elevator car in response to an upper direction call or a lower direction call from a passenger at a hall of a floor of the building. When the service can be provided, the main controller MC transmits a direction signal to the sub-controllers SC1-SCn turning on the response lamp UL or DL in a corresponding direction.
In case a car approaches a floor where the call is generated, the main controller MC transmits a instruction signal representing flickering the response lamp UL or DL to the sub-controllers SC1-SCn. After the passengers get in the elevator car, the main controller MC transmits an instruction signal representing turning off the response lamp UL or DL to the sub-controllers SC1-SCn. In addition, the main controller MC transmits to the sub-controllers SC1-SCn a floor information signal of indicating a floor where the elevator car is currently positioned.
The plurality of sub-controllers SC1-SCn are installed on each floor of the building. As the call button UB or DB is pushed, the sub-controllers SC1-SCn generate an elevator call signal, and transmit it to the main controller MC. In addition, each sub-controller SC1-SCn receives the ON instruction signal, the OFF instruction signal, the response lamp flickering instruction signal, and the car position information signal from the main controller MC, and controls an operation of the corresponding response lamp UL or DL and car position indicator CP1-CPn in accordance with the received instruction signals.
Three examples of the conventional technique of controlling the response to the call in the elevator system will now be explained.
A first example was described above. Here, the response lamp is turned on when the ON instruction signal of the response lamp is received from the main controller MC. However, as the plurality of sub-controllers are connected to the common serial communication line SL, if a communication is simultaneously generated, the ON operation may be delayed due to a communication delay.
A second example is that the sub-controllers SC1-SCn turn on the response lamp as soon as the call is generated. In this method, when the elevator car is not able to provide a service due to any abnormality of the serial communication line SL, the main controller MC, and the other components connected to the main controller MC, such as a speed controller, a position controller, a brake, various switches and safety devices, the passengers wait without receiving a service, thereby causing inconvenience.
As a third example, a timer is provided to the sub-controllers SC1-SCn. When the call is generated, the sub-controllers SC1-SCn directly turn on the response lamp. In case the ON instruction signal of the response lamp is not received from the main controller MC until a predetermined time set in the timer lapses, the response lamp is turned off. However, the passengers spend much time while the response lamp is turned on and off, and as a result, the service cannot be provided, thereby causing inconvenience to the passengers.